Individuals often wish to share digital files with others. In some cases, a particular individual may wish to simply share copies of files with others. In other instances, it may be desirable to allow others to modify centrally-stored copies of the files. There is currently a need for a system that allows individuals to share copies of files with others, and that optionally facilitates allowing certain recipients of the files to make changes to centrally-stored copies of those files. This can be useful in cases, for example, where it is desirable to have certain individuals collaborate to produce a particular file or collection of files, and to have other individuals monitor (but not participate in) the collaboration.